How to change sign

Question

i want to UPDATE column sign..
suppose if value is negative then
it should b possitive after update,or possitive shoud negative.
Table Structure
Fiied_1    Filed_2
1             -10
2              100after update i want
Table Structure
Fiied_1    Filed_2
1             10
2              -100Regards
Danish Hayder

Answer 1

Try this:
SQL> create table pos_neg (id number);
Table created.
SQL> insert into pos_neg values(-1);
1 row created.
SQL> insert into pos_neg values(100);
1 row created.
SQL> insert into pos_neg values(-34);
1 row created.
SQL> insert into pos_neg values(45);
1 row created.
SQL> select * from pos_neg;
        ID
        -1
       100
       -34
        45
SQL> select case when id>0 then -id
  2  when id<0 then abs(id) end
  3  from pos_neg;
CASEWHENID>0THEN-IDWHENID<0THE
                             1
                          -100
                            34
                           -45
SQL>
SQL> update pos_neg set id= case when id>0 then -id
2 when id<0 then abs(id) end; 
4 rows updated.
SQL> select * from pos_neg;
        ID
         1
      -100
        34
       -45
SQL>- - - - - - - - - - - - - - - - - - - - -
Kamran Agayev A. (10g OCP)
http://kamranagayev.wordpress.com
[Step by Step install Oracle on Linux and Automate the installation using Shell Script |http://kamranagayev.wordpress.com/2009/05/01/step-by-step-installing-oracle-database-10g-release-2-on-linux-centos-and-automate-the-installation-using-linux-shell-script/]
Edited by: Kamran Agayev A. on May 19, 2009 4:30 PM